Modeling and Optimal Design of Shorting Vias to Suppress Radiated Emission in High-Speed Alternating PCB Planes

Abstract

An analytical mode analysis of vias in the multilayered printed-circuit-board periphery is developed to suppress the electromagnetic radiation induced by ground bounce. After separating the even and odd modes in alternating planes, the far-field radiation of parallel plates is derived using Huygens' principle. It is mainly contributed by the odd mode excitation, while the even mode sets a lower bound on the radiation level from the system when shorting vias are inserted between alternating ground plates. For the odd-mode radiation, a canonical problem is then constructed and analytically solved by applying image theory. Based on that, a systematic approach to achieve the optimum suppression design is developed for the various geometry parameters of the shorting vias, including the pitch, radius, and distance to the board edge. Full-wave simulation and measurement are also presented and the good agreement with the theoretical prediction validates the correctness and efficiency of the present analysis and design.